Brancatisano's role in "Chasing Life," which was adapted from a Mexican series, is magnified because he's one of the few major male characters — and yes, he says, he knew from the start this would not be an ordinary romantic drama.

"But it's also not that unusual," he says. "April's situation is something a lot of people are going through. Almost everyone knows somebody who has cancer."

He says the cast doesn't know the endpoint of the first season, which was initially set for 13 episodes and then raised to 20.

"We go script to script," he says, "and that's really exciting. Apart from the fact you're always eager to see the next script, it keeps you in the moment. You're reacting the way the character would react then.

"It's like 'Lost,' where you never knew what was going to happen. It's about the journey, not about the end."